Study Notes on Scientific Investigation Fundamentals

Hypothesis

• A possible prediction and/or explanation of the relationship between two variables.
• Usually starts with the words 'to investigate …' and includes both variables.
• Describes what the investigation is trying to find out.

Aim

• The purpose of the investigation stated clearly.

The Independent (Manipulated) Variable

• This is the variable that the scientists will manipulate/control in the experiment.
• The independent variable typically appears on the X-axis of a graph.

The Dependent (Responding) Variable

• This variable is what reacts or responds to the independent variable.
• It is represented on the Y-axis of a graph.

The Controlled Variables

• All other variables that must be kept constant to ensure the validity of the investigation.
• Ensures that any effect observed is ONLY due to the change in the independent variable.

The Control

• A second setup in the investigation that allows for comparison with the results of the experiment.
• The control is identical to the experiment except that it excludes the variable that is being tested.

Accuracy

• Refers to the care taken when making measurements during the investigation.

Validity

• Refers to the experimental method and how appropriate it is in addressing the aim of the investigation.
• Keeping all other factors constant and identifying controlled variables helps in making an investigation valid.

Results

• The evidence produced during the investigation that will either support or refute the hypothesis.
• Results may be presented in various forms such as an extract, table, graph, or diagram.

Improving the Reliability of Results

• Results can be made more reliable through:
  • Repeating the investigation
  • Using a bigger sample size
  • Ensuring samples are taken randomly
  • Taking many readings to obtain an average reading

Conclusion

• This is directly linked to the aim of the investigation and serves to confirm or refute the hypothesis.